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Cells are known to be surrounded by nanoscale topography in their natural extracellular environment. The cell behavior, including morphology, proliferation, and motility of bovine pulmonary artery smooth muscle cells (SMC) were studied on poly(methyl methacrylate) (PMMA) and poly(dimethylsiloxane) (PDMS) surfaces comprising nanopatterned gratings with 350(More)
An existing model that relates the annihilation lifetime of positronium trapped in subnanometer pores to the average size of the pores is extended to account for positronium in any size pore and at any temperature. This extension enables the use of positronium annihilation lifetime spectroscopy in characterizing nanoporous and mesoporous materials, in(More)
The technique of positron annihilation lifetime spectroscopy ͑PALS͒ has been used to investigate the continuity and thermal stability of thin barrier layers designed to prevent Cu atom diffusion into porous silica, low-dielectric constant ͑k͒ films. Nanoglass™ K2.2-A10C ͑A10C͒, a porous organosilicate film, is determined to have interconnected pores with an(More)
Positronium annihilation lifetime spectroscopy is used to determine the pore-size distribution in low-dielectric thin films of mesoporous methylsilsesquioxane. A physical model of positronium trapping and annihilating in isolated pores is presented. The systematic dependence of the deduced pore-size distribution on pore shape/dimensionality and sample(More)
Lifetime analysis of positronium annihilating in nanometer voids is used to study the thermal expansion behavior of thin, Si-supported polystyrene films near the glass transition temperature T g. A reduction in void volume expansion is correlated with a reduction in the apparent T g as film thickness decreases. Our results can be fitted using a three-layer(More)
To direct and conduct research on high performance functional materials for nanotechnology, biotechnology and micro-/nano-electronics packaging applications; surface damage phenomena of polymers; structure-property relationship in polymers, blends, polyolefin films, fiber-reinforced composites, adhesives and nanocomposites; strengthening & toughening of(More)
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